The conventional process for removing halogen gasses such as chlorine (Cl.sub.2) from gas streams is to contact the gas stream with sodium hydroxide solution. The chlorine reacts with the sodium hydroxide to form sodium hypochlorite and sodium chloride.
Industrial waste incinerators are increasingly being used to destroy industrial wastes. When halogenated organic wastes are burned in an industrial waste incinerator, then the flue gas from the incinerator can contain halogens such as chlorine and/or bromine (Br.sub.2) which can not be discharged into the environment. Contacting the flue gas from an industrial incinerator with sodium hydroxide solution is an effective means of removing the halogen gas from the flue gas when the incinerator is burning halogenated organic wastes. However, the flue gas also contains carbon dioxide (for example, about 20% carbon dioxide by volume) and this carbon dioxide reacts with the sodium hydroxide solution to form sodium carbonate.
The reaction between carbon dioxide and sodium hydroxide increases the amount of sodium hydroxide needed to remove the halogens from the flue gas of the incinerator. In addition, the sodium hypochlorite formed is corrosive to ordinary steel or fiber reinforced plastic (FRP) process equipment and excessive amounts of sodium hypochlorite can not be discharged into the environment. It would be an advanced in the art of removing halogen gasses from gas streams containing carbon dioxide if a process were invented that reduced the amount of sodium hydroxide needed and which resulted in more environmentally acceptable output streams.